Process for the manufacture of hydroxythionaphthenes



United Stat v PROCESS FOR THE MANUFACTURE OF HYDROXYTHIONAPHTHENES NoDrawing. Application April 19, 1957 Serial No. 653,735

Claims priority, application Switzerland .lanuary 28, 1955 3 Claims.(Cl. 260-3305) This is a continuation-inpart of our copendingapplication Serial No. 561,157, filed January 24, 1956.

In the known processes for the manufacture of hy droxythionaphthenesfrom the corresponding arylthioglycollic acids, the latter are reactedwith phosphorus halides in an organic solvent to form the acid halides,and these are cyclized with aluminum chloride to form thehydroxythionaphthenes. The use of phosphorus halides entails thedisadvantage that phosphoric acids in the form of a sludge are formed asby-products and that this sludge has to be removed before the treatmentwith aluminum chloride is carried out. The sludge is difiicult tofilter, and the reaction product must therefore be allowed to standuntil all of the sludge has settled on the bottom of the reactionvessel. This requires several hours, entails the cumbersome work ofcleaning the reaction vessel, and thus reduces the output rate. Attemptshave been made to overcome these difliculties by using thionyl chlorideas acid-chlorinating agent, which is known to give as a rule, inaddition to the acid chloride, only volatile reaction products. However,if the soobtained acid chlorides are cyclized with aluminum chloride tothe corresponding hydroxythionaphthenes considerable resin formationtakes place and makes this procedure unsuitable.

It has now been found that said difilculties can be overcome in a simplemanner, by reacting an arylthioglycollic acid with at least thetheoretical amount of thionyl chloride in the presence of an inertorganic solvent and of, as catalyst, a formic acid amide of which theamide nitrogen atom is derived from a secondary amine, heating the soobtained arylthioglycollic acid halide in the pres ence of at least onemol of anhydrous aluminum chloride and isolating the resultinghydroxythionaphthene from the reaction mixture.

As arylthioglycollic acids there may be used preferably naphthalenethioglycollic acids, for example, naphthalene- 1- or 2-thioglycollicacid, 8-chloronaphtha1ene l-thioglycollie acid, or phenylthioglycollicacids, such as phenyl thioglycollic acid,2-chloro-l-methylbenzene-4-thioglycollic acid, 2:4 dichloro lmethylbenzene -thioglyc0llie acid, 2-chloro-1z4-dimethylbenzene 5thioglycollic acid, 4-chloro-2-methylbenzene-l-thioglycollic acid,4-chlorobenzene-l-thioglycollic acid,3,4-dichlorobenzene-1-thioglycollic acid and3-chlorobenzene-l-thioglycollic acid.

As formic acid amides of which the amide nitrogen atom is derived from asecondary amine, advantageously an aliphatic or heterocyclic secondaryamine, there may be used in the present process above all formic acidamides of which the amide nitrogen atom is bound, on the one hand, tothe HCO-group, and, on the other, to two alkyl groups which may form apart of a ring that may contain a further hetero atom, advantageously anoxygen atom. As such formic acid amides there may be used, for example,formic acid morpholide or formic acid piperidide, and especially formicacid dialkylamides, advantageously those which contain two alkyl groupsof low molecular weight, for example, formic acid dirnethyltent2,914,539 Patented Nov. 24, 1959 ice amide or formic acid diethylamide.The proportion of the formic acid amide used may vary within very widelimits, and if desired, the reaction may be carried out in the presenceof an inert diluent or solvent. Thus, for example, the acid used maybedissolved or suspended in dimethyl-formamide and the theoreticalquantity or a slight excess of the thionyl chloride added. It is alsopossible and in some cases advantageous to introduce the organic acidinto thionyl chloride or into a solvent inert towards acid chlorides,such as benzene, chlorobenzene, toluene, nitrobenzene, xylene or thelike, to add to the resulting solution or mixture a formic acid amide ofthe kind described above in excess or in an equivalent quantitycalculated on the acid or in a smaller quantity, for example, acatalytic quantity, that is to say a quantity considerably less than oneequivalent, for example, 0.05 to 0.1 of an equivalent, and to carry outthe reaction with thionyl chloride in the resulting reaction mixture.

The proportion of the thionyl chloride may likewise vary within widelimits. However, it is of advantageto convert the organic acid into itschloride, or a small excess.

The reaction may be carried out at-a raised temperature, for example, atthe boiling temperature of the reaction mixture or at a substantiallylower temperature. When the reaction is carried out in adialkyl-formamide alone the reaction generally sets in very easily atordinary temperature with the spontaneous evolution of heat, so that itis not necessary to heatthe'reaction mixture externally. The reaction isfinished in a very short time.

Then the anhydrous aluminum chloride may be added directly to thereaction mixture. However, it is of advantage to add the solution of theacid chloride as obtained in the first step to a suspension of thealuminum chloride in an inert organic solvent. The molecular proportionof aluminum chloride to arylthioglycollic acid must be at least 1:1. Insome cases it is advantageous to use a slight excess, for example, 5 to30% of aluminum chloride. However, no advantage is gained by using morethan 1.5 mols of aluminum chloride per mol of acid chloride. Thesubsequent treatment to effect'ring closure is advantageously carriedout at a raised temperature for example at 40-100 C. The presence of aformamide of the kind described above is also favorable for thisreaction stepin that the hydroxythionaphthenes formed are obtained in avery pure state and in very good yield.

The following examples illustrate the invention, the parts andpercentages being by weight unless otherwise stated, and therelationships of parts by weight to parts by volume being the same asthat of the kilogram to the liter.

' Example 1 115.5 parts of naphthalene-Z-thioglycollic acid areintroduced into a mixture of 245 parts by volume of chlorobenzene and4.1 parts by volume of dimethylformamide and 39.4 parts by volume ofthionyl chloride are added. The mixture is heated for 15 minutes at55-60 C., and then the greater part of the waste gas is removed from theresulting solution by blowing in dry air at the same temperature. Thesolution of the chloride is then introduced dropwise in the course of 30minutes intoa suspension, heated at 70-72 C., of 73 parts of anhydrousaluminum chloride in 450 parts by volume of chlorobenzene, and themixture is maintained for a further hour at 70-72 C. The reactionmixture is then poured on to ice, the chlorobenzene is distilled ofiwith steam under reduced pressure, and the residue is isolated byfiltration. The 2:1-naphthioindoxyl obtained in this quantitative yield.

Instead of 4.1 parts by volume of dimethyl formamide there can be usedwith equal success an equivalent quantity of diethyl formamide,di-n-butyl-formamide, N-formyl-morpholine or N-formyl-piperidine.

Example 2 73 parts of 8-chloro-naphthalene-l-thioglycollic acid aremixed with 270 parts by volume of chlorobenzene, 2.24 parts by volume ofdimethyl formamide, and 21.5 parts by volume of thionyl chloride. Themixture is heated at 55-60 C. for 30 minutes, and the greater part ofthe gases formed are expelled from the resulting solution by blowing indry air at the same temperature. The

solution of the thioglycollic acid chloride is then added dropwise inthe course of 30 minutes to a suspension of 51 parts of anhydrousaluminum chloride in 270 parts by volume of chlorobenzene having atemperature of 45-49" C. Themixture is maintained at 48-50 C. for 25minutes and then poured on to ice water and some hydro chloric acid. Thechlorobenzene is driven oil by steam distillation under reduced pressureand the residue isolated by filtration. On washing with cold water anddrying under reduced pressure at 40-60" C. there is obtained the8-chloro-1,2-naphthioindoxyl in a very pure state and practicallyquantitative yield.

Example 3 88 parts of 2,4-dichloro-5-methyl-phenyl-thioglycollic acidare mixed with 100 parts by volume of chlorobenzene, 2.7 parts by volumeof dimetyhlformamide, and 26 parts by volume of thionyl chloride. Themixture is heated at 55-60 C. for minutes, and the greater part oi thegases formed are expelled from the resulting so1u-. tion by blowing indry air at the same temperature. In the course or an hour thethioglycollic acid chloride is added dropwise to a suspension having atemperature 5264 C. of'5-1.5 parts of anhydrous aluminum chloride in 100parts by volume of chlorobenzene. The mixture is maintainedat 49-51" C.for 1 hour and then poured on to ice water and some hydrochloric acid.The chlorobenzene is driven oil by steam distillation under reducedpressure and the residue isolated by filtration. On washing with coldwater and drying under reduced pressure at 40 60 C. there is obtainedthe 4-methyl-5,7-dichlorohydroxythionaphthene in a very pure state andin practically quantitative yield. 7

By usingas starting material, instead of the 88 parts of 2,4dichloro-5-methyl-phenyl-thioglycollic acid, 80.7 parts of4-chloro-2,5-dimethyl-phenylthiog]ycollic acid and proceeding otherwiseas described in this example there is obtained withequal success the4,7-dimethyl-5-chlorohydrox'ythionaphthene.

Example 4 76 parts of 3-chloro-4-methyl-phenylthioglycollic acid aremixed with 100 parts by volume of chlorobenzene, 2.7 parts by volume ofdimethyltormamide, and 26 parts by volume of thionyl chloride. Themixture is heated at 55-60 C. for minutes, and the greater part of thegases formed are expelled from the resulting solution by blowing in dryair at the same temperature. The solution of the thioglycollic acidchloride is then added dropwise in the course of 1 hour to a suspensionhaving a temperature of 53-55 C. of 58 parts of anhydrous aluminumchloride in 150 parts by volume of chlorobenzene- The mixture ismaintained at 495 1 C. for 2% hours, thenpoured on to ice water and somehydrochloric acid. The chlorobenzene is driven oil by steam distillationunder reduced. pressure and the residue isolated by filtration. OnWashing with cold water and drying under reduced pressure at 4060 C.there is obtained the 5-methyl-6-chloro-hydroxythionaphthene in a verypure state and in practically quantitative yield.-

By using as starting material instead of the 3-chloro-4-methyl-phenylthioglycollic acid the 4-chloro-6-methyl 4phenylthioglycollic acid or the 4-chloro-phenylthioglycollic acid or the3,4-dichloro-phenylthioglycollic acid and proceeding otherwise asdescribed in this Example, there is obtained an equally good yield of5-chloro-7-methylor S-chloroor 5,6-dichloro-hydroxythionaphthene,respectively.

Example 5 60.8 parts of 3-chloro-phenylthioglycollic acid are mixed with100 parts by volume of chlorobenzene, 2.3 parts by volume of dimethylformamide and 22.3 parts by volume of thionyl chloride. The mixture isheated to 55-60 C. for 15 minutes, and the greater part of the gasesformed are expelled from the resulting solution by blowing in dry air atthe same temperature. The solution of the thioglycollic acid chloride isthen added dropwise in the course of 30 minutes to a suspension of 44parts of anhydrous aluminum chloride in 100 parts by volume ofchlorobenzene having a temperature of 57-60" C. The mixture ismaintained at 5759 C. for 30 minutes and then poured on to ice water andsome hydrochloric acid. The chlorobenzene is driven oil? by steamdistillation under reduced pressure and the residue isolated byfiltration. On washing with cold- Water and drying under reducedpressure at 4050 C. there is obtained 6-chloro-hydroxythionaphthene is avery pure state and in practically quantitative yield.

Example 6 anhydrous aluminum chloride in 200 parts by volume ofchlorobenzene. T he mixture is maintained at 45-48 C. for 25 minutes andthen cooled to 10-15 C. There is then added a solution of bromisatinchloride having a temperature of C., prepared from 66 parts gt 5-bromisatin by heating to 90400 C. for 5 hours with 64 parts ofphosphorus pentachloride in 750 parts by volume of chlorobenzene. Thereaction mass is then maintained at 54-56 C. for 1 hour. The mixture isthen poured on to a mixture of 1200 parts by volume of ice water and 48parts by volume of 30% hydrochloric acid, and freed from thechlorobenzene by steam distillation. The residue is filtered while warmand washed neutral to Congo With water. For further purification of thedyestuif, the residue is heated to 95 C. for an hour and a half with1200 parts by volume of water and parts by volume of 10 N-caustic sodasolution, then filtered at 80 C. and Washed neutral to Brilliant Yellowwith warm Water, On drying under reduced pressure at 6070 C. there areobtained 116 parts a dark indigo dyestuflf which dyes cotton from a vatfast gray-blue tints.

What is claimed is:

1. Process for the manufacture of hydroxythionaphthenes which consistsessentially of reacting one mol of an acid selected from the groupconsisting of naphthalenethioglycol1ic acid,chloronaphthalene-thioglycollic acid, phenyl-thioglycollic acid,chlorophenyl-thioglycollic acid, bromophenyl-thioglycollic acid,methylphenyl-thioglycollic acid and chloromethylphenyl-thioglycollicacid with at least one mol of thionyl chloride in the presence of aninert organic solvent and of a formic acid amide, as catalyst, selectedfrom the group consisting of the amides of the formulae O CHN and O CH-NO in which n is a whole number of at most 4, heating the resultingmixture in the presence of at least one mol of anyhdrous aluminumchloride and isolating the resulting hydroxythionaphthene from thereaction mixture.

2. Process for the manufacture of hydroxythionaphthenes which consistsessentially of reacting one mol of an acid selected from the groupconsisting of naphthalenethioglycollic acid,chloronaphthalene-thioglycollic acid, phenyl-thioglycollic acid,chlorophenyl-thioglycollic acid, bromophenyl-thioglycollic acid,methylphenyl-thioglycollic acid and chloromethylphenylthioglycollic acidwith at least one mol of thionyl chloride in the presence of an organicsolvent and dimethyl-formamide as catalyst, heating the resultingmixture in the presence of 1-1.5 mols anhydrous aluminum chloride andisolating the resulting hydroxythionaphthene from the reaction mixture.

3. Process for the manufacture of the hydroxythionaphthene of theformula 01 S-CH:

which consists essentially of reacting the8-chloro-naphthalene-l-thioglycollic acid with at least one mol ofthionyl chloride in the presence of chlorobenzene as solvent anddimethyl formamide, as catalyst, heating the resulting mixture in thepresence of 1-1.5 mols anhydrous aluminum chloride and isolating theresulting hydroxythionaphthene from the reaction mixture.

References Cited in the file of this patent UNITED STATES PATENTS1,765,703 Runne et al June 24, 1930 2,769,002 Buisson et a1 Oct. 30,1956 FOREIGN PATENTS 495,448 Germany Apr. 16. 1940

1. PROCESS FOR THE MANUFACTURE OF HYDROXYTHIONAPHTHENES WHICH CONSISTSESSENTIALLY OF REACTING ONE MOL OF AN ACID SELECTED FROM THE GROUPCONSISTING OF NAPHTHALENE-THIOGLYCOLLIC ACID,CHLORONAPHTHALENE-THIOGLYCOLLIC ACID, PHENYL-THIOGLYCOLLIC ACID,CHLOROPHENYL-THIOGLYCOLLIC ACID, BROMOPHENYL-THIOGLYCOLLIC ACID,METHYLPHENYL-THIOGLYCOLLIC ACID AND CHLOROMETHYLPHENYL-THIOGLYCOLLICACID WITH AT LEAST ONE MOL OF THIONYL CHLORIDE IN THE PRESENCE OF ANINERT ORGANIC SOLVENT AND OF A FORMIC ACID AMIDE, AS CATALYST, SELECTEDFROM THE GROUP CONSISTING OF THE AMIDES OF THE FORMULAE